11 Convergence insufficiency: are we making a difference in patients' lives or is it a waste of time!

Convergence insufficiency (CI) is a common condition that can impair visual performance and comfort during close visual work. This prospective study evaluated the effectiveness of interventions on clinical outcomes and quality-of-life using the adult strabismus quality-of-life questionnaire (AS20) in patients with CI.Data was extracted from a database collected at first consultation from 2015 to 2022. Demographics, interventions and outcomes of 84 patients with CI (mean age 47.0±24.9 years) were analysed.Orthoptic exercises were prescribed to 56% of patients, 32% received prisms, 15% received no treatment, with 3 discharged on the same day. At latest follow-up review, 22.6% were recommended to continue exercises, 28.6% had prisms, 1 underwent bimedial resection and 2 had botox. The median follow-up was 5.5(5.0-55)months, 88.1% were discharged with 29.8% following failure to attend and 9.5% deceased. Near-point of convergence (NPC) improved from a median of 15(6-50)cm to 10(6-30)cm. The median AS20 score at presentation were 100(30-100) and 47.5(0-100), and post-intervention were 100(80-100) and 77.5(12.5-97.5) for psychosocial and functional components, respectively.At the latest follow-up, the attendance failure rate was higher for exercises (36%) than for prisms (15%). Improvement was noted in NPC (33%) and mean AS20 scores was 9% higher psychosocially and 32.8% functionally, highlighting the benefits of intervention on patients' quality-of-life.This cohort provides valuable insights into the clinical management of CI, as evidenced by improvements in NPC and AS20 scores. However, the study also found that long-term compliance with treatment is intrinsically challenging, emphasising the importance of disease education.

Tuberculosis severity associates with variants and eQTLs related to vascular biology and infection-induced inflammation

Background

Tuberculosis (TB) remains a major public health problem globally, even compared to COVID-19. Genome-wide studies have failed to discover genes that explain a large proportion of genetic risk for adult pulmonary TB, and even fewer have examined genetic factors underlying TB severity, an intermediate trait impacting disease experience, quality of life, and risk of mortality. No prior severity analyses used a genome-wide approach.

Methods and findings

As part of our ongoing household contact study in Kampala, Uganda, we conducted a genome-wide association study (GWAS) of TB severity measured by TBScore, in two independent cohorts of culture-confirmed adult TB cases (n = 149 and n = 179). We identified 3 SNPs (P<1.0 x 10–7) including one on chromosome 5, rs1848553, that was GWAS significant (meta-analysis p = 2.97x10-8). All three SNPs are in introns of RGS7BP and have effect sizes corresponding to clinically meaningful reductions in disease severity. RGS7BP is highly expressed in blood vessels and plays a role in infectious disease pathogenesis. Other genes with suggestive associations defined gene sets involved in platelet homeostasis and transport of organic anions. To explore functional implications of the TB severity-associated variants, we conducted eQTL analyses using expression data from Mtb-stimulated monocyte-derived macrophages. A single variant (rs2976562) associated with monocyte SLA expression (p = 0.03) and subsequent analyses indicated that SLA downregulation following MTB stimulation associated with increased TB severity. Src Like Adaptor (SLAP-1), encoded by SLA, is highly expressed in immune cells and negatively regulates T cell receptor signaling, providing a potential mechanistic link to TB severity.

Conclusions

These analyses reveal new insights into the genetics of TB severity with regulation of platelet homeostasis and vascular biology being central to consequences for active TB patients. This analysis also reveals genes that regulate inflammation can lead to differences in severity. Our findings provide an important step in improving TB patient outcomes.

Clinical and Virologic Characteristics and Outcomes of Coronavirus Disease 2019 at a Cancer Center

BACKGROUND

High morbidity and mortality have been observed in patients with cancer and coronavirus disease 2019 (COVID-19); however, there are limited data on antimicrobial use, coinfections, and viral shedding.

METHODS

We conducted a retrospective cohort study of adult patients at the Seattle Cancer Care Alliance diagnosed with COVID-19 between February 28, 2020 and June 15, 2020 to characterize antimicrobial use, coinfections, viral shedding, and outcomes within 30 days after diagnosis. Cycle threshold values were used as a proxy for viral load. We determined viral clearance, defined as 2 consecutive negative results using severe acute respiratory syndrome coronavirus 2 reverse-transcription polymerase chain reaction results through July 30, 2020.

RESULTS

Seventy-one patients were included with a median age of 61 years; 59% had a solid tumor. Only 3 patients had documented respiratory bacterial coinfection. Empiric antibiotics for pneumonia were prescribed more frequently early in the study period (February 29-March 28, 2020; 12/34) compared to the later period (March 29-June 15, 2020; 2/36) (P = .002). The median number of days from symptom onset to viral clearance was 37 days with viral load rapidly declining in the first 7-10 days after symptom onset. Within 30 days of diagnosis, 29 (41%) patients were hospitalized and 12 (17%) died. Each additional comorbidity was associated with 45% lower odds of days alive and out of hospital in the month following diagnosis in adjusted models.

CONCLUSIONS

Patients at a cancer center, particularly those with multiple comorbidities, are at increased risk of poor outcomes from COVID-19. Prolonged viral shedding is frequently observed among cancer patients, and its implications on transmission and treatment strategies warrant further study.

370. Clinical Features and Outcomes of COVID-19 Infection Among Cancer Patients in Seattle, Washington

Background

High morbidity and mortality has been observed with COVID-19 infection; however, there are limited data on clinical characteristics including exposures, coinfections, and antimicrobial use among cancer patients. We aimed to better characterize clinical features and outcomes in this population.

Methods

We conducted a retrospective chart review of consecutive patients at the Seattle Cancer Care Alliance diagnosed with SARS-CoV-2 infection by RT-PCR between February 28, 2020 and May 3, 2020. We obtained demographic and clinical data including coinfections, antimicrobial use and outcomes at 30 days after diagnosis.

Results

Of 60 patients reviewed, the median age was 62 years (range 22–98) and 43% were male. 34 (57%) patients had solid tumors and 16 (27%) hematologic malignancies. Breast (12%), colorectal (8%) and non-Hodgkin lymphoma (8%) were the most prevalent cancers. 34 (57%) had ≥ 2 comorbidities. The majority of identified exposures were from long-term care facilities (LTCF) (27%) or household contacts (25%) (Fig 1). The most common symptoms at diagnosis were cough (72%), fevers/chills (57%), shortness of breath (38%), nasal congestion/rhinorrhea (35%), and diarrhea (30%). 18 (31%) patients were prescribed at least one course of antibiotics within 30 days of diagnosis; antibiotics were prescribed to 54% of hospitalized patients (Fig 2). 6 (10%) had a documented bacterial infection; of these, 3 were respiratory coinfections. No viral or fungal copathogens were reported. 26 (43%) patients were hospitalized, 9 (15%) admitted to intensive care, and one (2%) required mechanical ventilation. 12 (20%) died within 30 days of diagnosis (Fig 3); of these, 10 (83%) had ≥ 2 comorbidities and 8 (67%) had LTCF exposure.

Conclusion

COVID-19 is associated with significant morbidity and mortality in cancer patients, particularly among older age groups with multiple comorbidities and those with LTCF exposure. More than half of cases appeared to acquire SARS-CoV-2 from LTCF or household exposures, indicating need for infection prevention and family/caregiver education. Despite few documented bacterial coinfections, antibiotic use within 30 days of diagnosis was common and likely empiric due to limited diagnostics in the era of COVID-19.

Disclosures

Steven A. Pergam, MD, MPH, Chimerix, Inc (Scientific Research Study Investigator)Global Life Technologies, Inc. (Research Grant or Support)Merck & Co. (Scientific Research Study Investigator)Sanofi-Aventis (Other Financial or Material Support, Participate in clinical trial sponsored by NIAID (U01-AI132004); vaccines for this trial are provided by Sanofi-Aventis) Alpana Waghmare, MD, Amazon (Grant/Research Support)Amazon (Employee, Shareholder)Ansun Biopharma (Scientific Research Study Investigator)Kyorin Pharmaceuticals (Advisor or Review Panel member)

Circulating tumor DNA guided adjuvant chemotherapy in stage II colon cancer (MEDOCC-CrEATE): study protocol for a trial within a cohort study

BACKGROUND

Accurate detection of patients with minimal residual disease (MRD) after surgery for stage II colon cancer (CC) remains an urgent unmet clinical need to improve selection of patients who might benefit form adjuvant chemotherapy (ACT). Presence of circulating tumor DNA (ctDNA) is indicative for MRD and has high predictive value for recurrent disease. The MEDOCC-CrEATE trial investigates how many stage II CC patients with detectable ctDNA after surgery will accept ACT and whether ACT reduces the risk of recurrence in these patients.

METHODS/DESIGN

MEDOCC-CrEATE follows the 'trial within cohorts' (TwiCs) design. Patients with colorectal cancer (CRC) are included in the Prospective Dutch ColoRectal Cancer cohort (PLCRC) and give informed consent for collection of clinical data, tissue and blood samples, and consent for future randomization. MEDOCC-CrEATE is a subcohort within PLCRC consisting of 1320 stage II CC patients without indication for ACT according to current guidelines, who are randomized 1:1 into an experimental and a control arm. In the experimental arm, post-surgery blood samples and tissue are analyzed for tissue-informed detection of plasma ctDNA, using the PGDx elio™ platform. Patients with detectable ctDNA will be offered ACT consisting of 8 cycles of capecitabine plus oxaliplatin while patients without detectable ctDNA and patients in the control group will standard follow-up according to guideline. The primary endpoint is the proportion of patients receiving ACT when ctDNA is detectable after resection. The main secondary outcome is 2-year recurrence rate (RR), but also includes 5-year RR, disease free survival, overall survival, time to recurrence, quality of life and cost-effectiveness. Data will be analyzed by intention to treat.

DISCUSSION

The MEDOCC-CrEATE trial will provide insight into the willingness of stage II CC patients to be treated with ACT guided by ctDNA biomarker testing and whether ACT will prevent recurrences in a high-risk population. Use of the TwiCs design provides the opportunity to randomize patients before ctDNA measurement, avoiding ethical dilemmas of ctDNA status disclosure in the control group.

TRIAL REGISTRATION

Netherlands Trial Register: NL6281/NTR6455 . Registered 18 May 2017, https://www.trialregister.nl/trial/6281.

Computer-Based Exercises in Anemia Diagnosis (PlanAlyzer)

PlanAlyzer is a microcomputer-based, event-driven system for instructional research in medical education. Aimed at the second year medical student, PlanAlyzer elicits and critiques a student´s approach to the diagnosis of a common medical disorder. In this paper we discuss the concept, development, implementation and formative evaluation of the PlanAlyzer system for the evaluation of anemia.

Abstract P2-02-20: Withdrawn

This abstract was withdrawn by the authors.

Collaborating to Compete: Blood Profiling Atlas in Cancer (BloodPAC) Consortium

The cancer community understands the value of blood profiling measurements in assessing and monitoring cancer. We describe an effort among academic, government, biotechnology, diagnostic, and pharmaceutical companies called the Blood Profiling Atlas in Cancer (BloodPAC) Project. BloodPAC will aggregate, make freely available, and harmonize for further analyses, raw datasets, relevant associated clinical data (e.g., clinical diagnosis, treatment history, and outcomes), and sample preparation and handling protocols to accelerate the development of blood profiling assays.

A Case of Early Neurosyphilis

INTRODUCTION

Neurosyphilis is an infection of the central nervous system by Treponema pallidum, which can occur after the initial syphilis infection. Although commonly associated with late stage disease, patients with early neurosyphilis may present with acute syphilitic meningitis, meningovascular syphilis, or uveitis.

CASE

A 28 year old man with a past medical history of HIV (CD4 364);, and recent diagnosis of uveitis presented to the Emergency Department with a positive RPR result. His visual acuity had been gradually declining over the past few months. He denied painless or painful ulcerating lesions on his penis, or scrotum, difficulty concentrating, dermatitis on the soles/palms, or difficulty with proprioception. Physical exam was notable for atrophic hyperpigmented polycyclic, annular plaques and patches along the hairline as well as several areas of confluent hyperpigmented polycyclic plaques and nodules on the patient's face, back, left arm, and right posterior leg. Fundoscopic exam revealed bilateral posterior uveitis and chorioretinitis. Evaluation of cerebrospinal fluid revealed a lymphocytic pleocytosis with a positive VDRL and FTA-ABS. Aqueous crystalline penicillin G was initiated for treatment of early neurosyphilis. Within six hours of beginning the infusion, the patient had a documented temperature of 101.8°F, heart rate of 128 beats per minute, blood pressure 142/84, with generalized malaise and headache. Fever and tachycardia resolved over the next 12 hours, with weakness and headache resolving within 1-2 days. His symptom complex was consistent with the Jarisch-Herxheimer reaction. Histopathology of skin biopsy of the back showed perivascular inflammation and rare spirochetes, consistent with secondary syphilis. The patient completed 14 days of aqueous crystalline penicillin G and was discharged after receiving the first of three benzathine penicillin injections.

DISCUSSION

The initial manifestations of syphilis in this patient were posterior uveitis and pruritic skin plaques. His diagnosis should be appropriately classified as secondary syphilis with concomitant symptomatic early neurosyphilis, requiring 14 days of aqueous crystalline penicillin G. This type of presentation is not specific to immunocompromised populations and must be considered even in the general population. Making the diagnosis of early neurosyphilis, regardless of stage, is critical, as it necessitates a longer duration of treatment. Furthermore, clinicians should be reminded of the profound immunologic reaction, Jarisch-Herxheimer, which may occur when treating any treponemal disease.

Study protocol for a natural experiment in a lower socioeconomic area to examine the health-related effects of refurbishment to parks including built-shade (ShadePlus)

INTRODUCTION

Parks in disadvantaged suburbs often have low quality and few amenities, which is likely to result in them being underutilised for recreation and physical activity. Refurbishment of parks, including shade, walking paths and other amenities, may have broad health-related benefits.

METHODS AND ANALYSIS

The study design, methods and planned analyses for a natural experiment examining the effects of refurbishments including built-shade added to parks in disadvantaged outer suburbs of Melbourne are described. Three intervention parks and three comparison parks matched for equivalence of park and neighbourhood characteristics were selected. Using mixed methods, the outcomes will be assessed during three consecutive spring-summer periods (T1: 2013-2014; T2: 2014-2015: T3: 2015-2016). Primary outcomes included: observed park use, physical activity and shade use. Self-reported social connectedness, community engagement and psychological well-being were assessed as secondary outcomes.

ETHICS AND DISSEMINATION

This study was approved by Cancer Council Victoria's Human Research Ethics Committee. Studies such as ShadePlus can improve understanding of the broader effects of park refurbishments (including physical activity levels and sun protection behaviours, as well as social connectedness and psychological well-being). The study findings will be disseminated through established urban planning and parks and recreation networks, peer review publications and conference presentations.

Improving the care of patients with severe open fractures of the tibia: the effect of the introduction of Major Trauma Networks and national guidelines

AIMS

The management of open lower limb fractures in the United Kingdom has evolved over the last ten years with the introduction of major trauma networks (MTNs), the publication of standards of care and the wide acceptance of a combined orthopaedic and plastic surgical approach to management. The aims of this study were to report recent changes in outcome of open tibial fractures following the implementation of these changes.

PATIENTS AND METHODS

Data on all patients with an open tibial fracture presenting to a major trauma centre between 2011 and 2012 were collected prospectively. The treatment and outcomes of the 65 Gustilo Anderson Grade III B tibial fractures were compared with historical data from the same unit.

RESULTS

The volume of cases, the proportion of patients directly admitted and undergoing first debridement in a major trauma centre all increased. The rate of limb salvage was maintained at 94% and a successful limb reconstruction rate of 98.5% was achieved. The rate of deep bone infection improved to 1.6% (one patient) in the follow-up period.

CONCLUSION

The reasons for these improvements are multifactorial, but the major trauma network facilitating early presentation to the major trauma centre, senior orthopaedic and plastic surgical involvement at every stage and proactive microbiological management, may be important factors.

TAKE HOME MESSAGE

This study demonstrates that a systemised trauma network combined with evidence based practice can lead to improvements in patient care.

Plastic surgical operative workload in major trauma patients following establishment of the major trauma network in England: A retrospective cohort study

INTRODUCTION

The introduction of major trauma centres (MTCs) in England has led to 63% reduction in trauma mortality.(1) The role of plastic surgeons supporting these centres has not been quantified previously. This study aimed to quantify plastic surgical workload at an urban MTC to determine the contribution of plastic surgeons to major trauma care.

METHODS

All Trauma Audit and Research Network (TARN)-recorded major trauma patients who presented to an urban MTC in 2013 and underwent an operation were identified retrospectively. Patients who underwent plastic surgery were identified and the type and date of procedure(s) were recorded. The trauma operative workload data of another tertiary surgical specialty and local historical plastics workload data from pre-MTC go-live were collected for comparison.

RESULTS

Of the 416 major trauma patients who required surgical intervention, 29% (n = 122) underwent plastic surgery. Of these patients, 43% had open lower limb fractures, necessitating plastic surgical involvement according to British Orthopaedic Association Standards for Trauma (BOAST) 4 guidance. The overall plastic surgery operative workload increased sevenfold post-MTC go-live. A similar proportion of the same cohort required neurosurgery (n = 115; p = 0.589).

DISCUSSION

This study quantifies plastic surgery involvement in major trauma and demonstrates that plastic surgical operative workload is at least on par with other tertiary surgical specialties. It also reports one centre's experience of a significant change in plastic surgery activity following designation of MTC status. The quantity of plastic surgical operative workload in major trauma must be considered when planning major trauma service design and workforce provision, and for plastic surgical postgraduate training.

Metabolite content profiling of bottlenose dolphin exhaled breath

Changing ocean health and the potential impact on marine mammal health are gaining global attention. Direct health assessments of wild marine mammals, however, is inherently difficult. Breath analysis metabolomics is a very attractive assessment tool due to its noninvasive nature, but it is analytically challenging. It has never been attempted in cetaceans for comprehensive metabolite profiling. We have developed a method to reproducibly sample breath from small cetaceans, specifically Atlantic bottlenose dolphins (Tursiops truncatus). We describe the analysis workflow to profile exhaled breath metabolites and provide here a first library of volatile and nonvolatile compounds in cetacean exhaled breath. The described analytical methodology enabled us to document baseline compounds in exhaled breath of healthy animals and to study changes in metabolic content of dolphin breath with regard to a variety of factors. The method of breath analysis may provide a very valuable tool in future wildlife conservation efforts as well as deepen our understanding of marine mammals biology and physiology.

Volatile emanations from in vitro airway cells infected with human rhinovirus

Respiratory viral infections such as human rhinovirus (HRV) can lead to substantial morbidity and mortality, especially in people with underlying lung diseases such as asthma and COPD. One proposed strategy to detect viral infections non-invasively is by volatile organic compound (VOC) assessment via analysis of exhaled breath. The epithelial cells are one of the most important cell lines affected during respiratory infections as they are the first line of pathogen defense. Efforts to discover infection-specific biomarkers can be significantly aided by understanding the VOC emanations of respiratory epithelial cells. Here we test the hypothesis that VOCs obtained from the headspace of respiratory cell culture will differentiate healthy cells from those infected with HRV. Primary human tracheobronchial cells were cultured and placed in a system designed to trap headspace VOCs. HRV-infected cells were compared to uninfected control cells. In addition, cells treated with heat-killed HRV and poly(I:C), a TLR3 agonist, were compared to controls. The headspace was sampled with solid-phase microextraction fibers and VOCs were analyzed by gas chromatography/mass spectrometry. We determined differential expression of compounds such as aliphatic alcohols, branched hydrocarbons, and dimethyl sulfide by the infected cells, VOCs previously associated with oxidative stress and bacterial infection. We saw no major differences between the killed-HRV, poly(I:C), and control cell VOCs. We postulate that these compounds may serve as biomarkers of HRV infection, and that the production of VOCs is not due to TLR3 stimulation but does require active viral replication. Our novel approach may be used for the in vitro study of other important respiratory viruses, and ultimately it may aid in identifying VOC biomarkers of viral infection for point-of-care diagnostics.

Novel interactive effects of darkness and retinoid signaling in the ability to form long-term memory following aversive operant conditioning

The vitamin A metabolite, retinoic acid, is important for memory formation and hippocampal synaptic plasticity in vertebrate species. In our studies in the mollusc Lymnaea stagnalis, we have shown that retinoic acid plays a role in memory formation following operant conditioning of the aerial respiratory behaviour. Inhibition of either retinaldehyde dehydrogenase (RALDH) or the retinoid receptors prevents long-term memory (LTM) formation, whereas synthetic retinoid receptor agonists promote memory formation by converting intermediate-term memory (ITM) into LTM. In this study, animals were exposed to constant darkness in order to test whether light-sensitive retinoic acid would promote memory formation. However, we found that exposure to constant darkness alone (in the absence of retinoic acid) enhanced memory formation. To determine whether the memory-promoting effects of darkness could override the memory-inhibiting effects of the retinoid signaling inhibitors, we exposed snails to RALDH inhibitors or a retinoid receptor antagonist in constant darkness. We found that darkness overcame the inhibitory effects of RALDH inhibition, but did not overcome the inhibitory effects of the retinoid receptor antagonist. We also tested whether constant darkness and training affected the mRNA levels of the retinoid metabolic enzymes RALDH and Cyp26, or the mRNA levels of the retinoid receptors, but found no significant effect. Overall, these data demonstrate an interaction between environmental light conditions and the retinoid signaling pathway, which influence long-term memory formation in a mollusc.

Multidrug resistance protein gene expression in Trichoplusia ni caterpillars

Many insect species exhibit pesticide-resistant phenotypes. One of the mechanisms capable of contributing to resistance is the overexpression of multidrug resistance (MDR) transporter proteins. Here we describe the cloning of three genes encoding MDR proteins from Trichoplusia ni: trnMDR1, trnMDR2 and trnMDR3. Real-time quantitative PCR (qPCR) detected trnMDR mRNA in the whole nervous system, midgut and Malpighian tubules of final instar T. ni caterpillars. To test whether these genes are upregulated in response to chemical challenge in this insect, qPCR was used to compare trnMDR mRNA levels in unchallenged insects with those of insects fed the synthetic pyrethroid, deltamethrin. Only limited increases were detected in a single gene, trnMDR2, which is the most weakly expressed of the three MDR genes, suggesting that increased multidrug resistance of this type is not a significant part of the response to deltamethrin exposure.

What is the most reliable imaging modality for small colonic polyp characterization? Study of white-light, autofluorescence, and narrow-band imaging

BACKGROUND AND STUDY AIMS

In vivo optical diagnosis of small colorectal polyps has potential clinical and cost advantages, but requires accuracy and high interobserver agreement for clinically acceptability. We aimed to assess interobserver variability and diagnostic performance of endoscopic imaging modalities in characterizing small colonic polyps.

METHODS

High quality still images of 80 polyps < 1 cm were recorded using white-light endoscopy (WLE), autofluorescence imaging (AFI) and narrow-band imaging with and without magnification (NBI and NBImag). All images were assessed for quality, prediction of polyp histology, and vascular pattern intensity (with NBI) by nine experienced colonoscopists (four experts in advanced imaging) from five UK centers. Interobserver agreement (kappa statistic), sensitivity, specificity, and accuracy were calculated compared with histopathological findings.

RESULTS

Interobserver agreement for predicting polyp histology using NBImag was significantly better for experts (κ = 0.63, substantial) compared with nonexperts (κ = 0.30, fair; P < 0.001), and was moderate for all colonoscopists with WLE, AFI and NBI. Interobserver agreement for vascular pattern intensity using NBI was 0.69 (substantial) for experts and 0.57 (good) for nonexperts. NBImag had higher sensitivity than WLE (experts, 0.93 vs. 0.68, P < 0.001; nonexperts, 0.90 vs. 0.52, P < 0.001) and higher overall accuracy (experts, 0.76 vs. 0.64, P = 0.003; nonexperts 0.61 vs. 0.40, P < 0.001). AFI had worse accuracy than WLE for both expert colonoscopists (0.53 vs. 0.64, P = 0.02) and nonexperts (0.32 vs. 0.40, P = 0.04).

CONCLUSIONS

Of the imaging modalities tested, NBImag appeared to have the best overall accuracy and interobserver agreement, although not adequate for in vivo diagnosis. NBI and AFI did not have better sensitivity, specificity, or accuracy compared with WLE.

Modulation of type I IFN induction by a virulence determinant within the alphavirus nsP1 protein

Alphaviruses are mosquito-borne viruses that cause serious human and animal diseases. Previous studies demonstrated that a determinant within the nsP1/nsP2 cleavage domain of the virulent Sindbis AR86 virus played a key role in regulating adult mouse virulence without adversely affecting viral replication. Additional characterization of this determinant demonstrated that a virus with the attenuating mutation induced more type I IFN production both in vivo and in vitro. Interestingly, this phenotype was not specific to the Sindbis AR86 virus, as a similar mutation in a distantly related alphavirus, Ross River Virus (RRV), also led to enhanced IFN induction. This effect was independent of virus-induced host shutoff, since IRF-3 phosphorylation, which occurs independently of de novo host transcription/translation, was induced more robustly in cells infected with the mutant viruses. Altogether, these results demonstrate that critical determinants within the nsP1/nsP2 cleavage domain play an important role in regulating alphavirus-induced IFN responses.

Clostridial typhlitis associated with topical antibiotic therapy in a Syrian hamster

A Syrian hamster that had been treated with topical antibiotic ointment for 10 days following injuries sustained during fighting was presented moribund. Postmortem and microscopic examinations revealed lesions consistent with clostridial typhlitis and enteritis. Anaerobic culture of caecal contents resulted in the isolation of two Clostridium species, and caecal contents contained Clostridium difficile enterotoxins. Based on these findings, a diagnosis of acute C. difficile enterotoxaemia was made. This report discusses the pathogenesis of C. difficile enterotoxaemia and the potential role of topical antibiotic ointment therapy in initiating the disease.

Evaluation of hard tissue replacement composite graft material as a ridge preservation/augmentation material in conjunction with immediate hydroxyapatite-coated dental implants

BACKGROUND

Immediate placement of dental implants (DI) in fresh extraction sockets is associated with remaining voids around the DI and often a partial dehiscence or thin facial alveolar plate. Bone replacement grafts are often used to correct these problems. This study evaluated the use of a layered composite of PMMA (poly-methyl-methacrylate), PHEMA (poly-hydroxyl-ethyl-methacrylate), and calcium hydroxide grafts (HTR) as a ridge preservation/ augmentation material used in conjunction with an immediate DI placement technique.

METHODS

Twenty-three patients requiring 1 or 2 extractions that were treatment planned for immediate DI placement received 4.0 or 3.25 mm diameter hydroxyapatite-coated cylindrical implants in the extraction sockets. HTR was used to fill the remaining socket void and enhance the facial ridge width. A collagen hemostatic was placed to cover the DI sites, flaps released, and primary closure attempted with sutures. DI uncovering was performed at about 6 months. Measurements were taken to the nearest 0.5 mm of the internal socket width and total ridge width at DI placement and uncovering.

RESULTS

Thirty DIs were placed in the 23 patients. Mean initial internal socket width was 6.9 mm. The total ridge width showed a mean change from 9.1 mm to 8.4 mm; 60% of the areas showed a net increase or no change, while 40% showed a decrease in overall ridge width. DI success rate was 97% out to 6 months of loading.

CONCLUSION

The results of this study suggest that HTR is a useful adjunct in the placement of immediate DIs for filling of socket voids and preservation of ridge width.